"This helps us understand how movement is initiated in animals," Libersat said. "We know how movement itself is generated, but to understand what makes an animal decide to move or not to move is a different issue."

Parasite Strategies

The jewel wasp is the only parasite known to inject its venom directly into its host's brain.

But other parasites also control the behavior of their hosts, said David Richman, curator of the Arthropod Museum at New Mexico State University in Las Cruces, who was not involved in the new study.

"This is not uncommon. There are a tremendous number of parasites, and they all have different strategies for survival and for propagation of their species," Richman said.

The behaviors of land snails, grasshoppers, and types of ants, for example, can all be affected by parasites.